As tensions between the U.S. and Iran rise, a series of incidents has put a strategic maritime waterway back into the spotlight: The Strait of Hormuz. WSJ’s John Simons explains. Photo: Getty Images As tensions with Iran began escalating last month, President Trump made a startling statement: The U.S. shouldn’t be bearing the burden of protecting the flow of oil tankers past Iranian waters and through the Strait of Hormuz, one of the principal assignments the U.S. has accepted for the last four decades. Instead, he said, China and Japan depend far more on Persian Gulf oil than does the U.S. these days, so they should protect their own ships. “We don’t even need to be there in that the U.S. has just become (by far) the…